Matsushita Electronics Corporation

Matsushita Electric Industrial Co., Ltd.

Toshiyoshi Oga

Masaru Saito

Shunji Asai

Nobuyuki Tsubakihara

Masaru Saitoh

Noriyuki Uchida

Ikuhiro Okuno

Masashi Sangen

Hidehito Kawahara

Toshifumi Kondoh

Akihito Wakamiya

Masatoshi Sudou

Kozo Shirai

A fluorescent lamp includes two glass outer tubes ( ), a bridge junction ( ), and first glass inner tubes ( ). One end of each of the glass outer tubes is closed, and the other end is sealed with stems ( ) for supporting electrodes ( ). A phosphor is applied to the inside surface of each of the glass outer tubes. The bridge junction connects the glass outer tubes at the other end portion to form a discharge space inside the glass outer tubes. The first glass inner tubes are provided in the glass outer tubes, respectively. A phosphor is applied to the surface of each of the first glass inner tubes. One end of each of the first glass inner tubes is open and disposed at the closed ends of the glass outer tubes, and the other end is sealed with the tips of the stems so that the electrodes are positioned in the first glass inner tubes.

Fluorescent lamp

A fluorescent lamp capable of fully securing a portion for containing a mercury amalgam pellet and reliably preventing the mercury amalgam pellet from moving toward the inside a discharge tube, and a method for manufacturing the fluorescent lamp. The fluorescent lamp includes a glass tube having a fluorescent substance layer on the inner surface, a sealed portion formed at an end of the glass tube, a slender glass tube having an inner space that is in communication with the inside of the glass tube and is not in communication with the outside of the glass tube, and a mercury amalgam pellet contained in the slender glass tube. The slender glass tube has a small-diameter part with an inner diameter smaller than the diameter of the mercury amalgam pellet and a large-diameter part with an inner diameter larger than the diameter of the mercury amalgam pellet. The slender glass tube is welded to the glass tube so that the small-diameter part is placed in the sealed portion and the large-diameter part is placed further away from the glass tube than the smaller-diameter part.

Fluorescent lamp and method for manufacturing the fluorescent lamp

Fluorescent lamp with amalgam container

A method for manufacturing a glass tube used for a fluorescent lamp having an arc tube constructed by joining a plurality of glass tubes is provided. According to this method, a straight glass tube held at both ends is rotated, and a predetermined cutting portion of the glass tube is softened by heating, and then the glass tube is moved in the heated state in the direction toward the predetermined cutting portion to form a glass accumulated portion at the area of the predetermined cutting portion. Next, the glass tube is drawn away in the direction receding from the predetermined cutting portion, and the predetermined cutting portion of the glass tube is cut into two glass tubes having self-closing end walls. In this way, the end walls of the self-closed glass tubes can be formed thicker and more uniform compared to those obtained by the conventional techniques, and the mechanical strength of the end walls also can be improved. As a result, the defective percentage of the lamps during the manufacturing process and on the market due to cracks, leakage, or damages in the end walls of the glass tubes can be reduced.

Method for manufacturing a fluorescent lamp

In a method for manufacturing a fluorescent lamp, four dual tubes that are previously manufactured are held at a distance in such a manner that the dual tubes can move horizontally. Four portions for connection are simultaneously heated, and two of the dual tubes are simultaneously moved horizontally to form bridge portions to provide tube assemblies. Furthermore, annealing after bridge connection and the connection of tube assemblies with a bridge are performed simultaneously. Thus, a compact fluorescent lamp comprising eight glass tubes that are connected with bridges to form continuous discharge paths can be obtained. According to the manufacturing method, bridge connection can be performed in a small space and with high productivity, and a fluorescent lamp having a good quality with minor variations in the quality of the bridge portions can be provided.

Two arc tubes which are to be connected are held at different levels. Predetermined portions in the vicinity of an end of each arc tube are evenly heated and softened by a flame of a burner from the side. An air flow is supplied to blowing up the softened portion to form a semi-junction bridge having a circular cross-section and a flat connecting face. The thickness of the wall of the semi-junction bridge is even. The arc tubes having the semi-junction bridges are disposed on the same plane and one arc tube is moved to the other to connect the semi-junction bridges while the connecting faces are softened.

A device for manufacturing a spiral fluorescent tube is disclosed. The device includes a rod aerially supported in a first predetermined direction; a first clamp supporting a straight fluorescent tube in a second direction which is at right angles to the first predetermined direction; heating device for heating a part of the straight fluorescent tube, which is not facing the rod, to a glass softening temperature; two second clamps disposed in a direction parallel to the rod for clamping ends of the straight fluorescent tube; and device for winding the straight fluorescent tube around the rod by rotating the two second clamps in opposite directions to each other around an axis of the rod while shifting the two second clamps away from each other in a direction parallel to the first predetermined direction.

Apparatus for manufacturing spiral fluorescent tube

A fluorescent tube which is used for bulb-type fluorescent lamps is spirally wound, so that the effective length of the tube is increased. While a fluorescent tube is kept vertical, it is rotated and heated evenly at the part to be wound to a glass softening temperature or above by a heating device. The rotation of the fluorescent tube is stopped, and the part which is not facing a rod are heated. Then, the tube is clamped from a horizontal direction by a pair of clamps, and is wound around the rod at least 2.5 times by rotating the clamp arms in opposite directions while the arms gradually shift away from each other.

Method of manufacturing a spiral fluorescent tube

This invention provides a compact, efficient and well-designed circular fluorescent lamp with high output power. The circular fluorescent lamp has less non-luminant region and good characteristics of luminous intensity distribution, and keeps high level of lamp lumen output. Circular arc tubes are disposed concentrically on the same plane. Electrodes are attached to the tube-end parts of the one side of the circular arc tubes respectively, and the other tube-end parts of non-electrode side are sealed. The circular arc tubes are joined each other near the tube-end parts of the non-electrode side with a bridge-jointed portion, so that a discharge path is formed between the electrodes inside the arc tubes. The tube outer diameter of the circular arc tubes is 14 mm, the circle outer diameter of the outer circular arc tube is 150 mm, and the circle inner diameter of the inner arc tube is 90 mm. The distance measured along the center line of the tube from the point corresponding radially to the end part of the bridge-jointed portion to the sealed tube-end part of the outer circular arc tube is 11 mm, and the distance measured along the center line of the tube from the point corresponding radially to the end part of the bridge-jointed portion to the sealed tube-end part of the inner circular arc tube is 6 mm.

Growing community of inventors

Shiga, Japan

Toshiyoshi Oga